An Ontario man who had multiple sclerosis died in October after controversial surgery to open up a blocked neck vein that he believed was causing his disease. St. Catherines resident Mahir Mostic, 35, died one day after Costa Rican doctors tried to fix a blood clot that emerged shortly after his original surgery in June. Mostic had a fast-moving type of MS that prevented him from walking, so he was willing to risk neck vein surgery, which is not approved by Health Canada. After the surgery, “He started feeling better and got his energy back,” his girlfriend, Bedrana Jelin told CBC News. Then, his symptoms worsened again and he tried to see a specialist in Canada. “They didn’t want to touch him because he was done outside of Canada,” Jelin said. That’s when he flew back to Costa Rica, where Dr. Marcial Fallas treated him with blood-thinning medication to remove a clot that had formed. Fallas says the blood thinners likely caused his death. Dr. Barry Rubin, the head of vascular surgery at Toronto’s University Health Network, says it would have been safer to leave the clot alone. He also said he treated an MS patient recently who had blood clots after receiving neck vein surgery in Mexico. In Canada and the U.S., there are several research studies underway to determine whether vein narrowing surgery is safe and effective.